Traditional systems for video production either rely on uncompressed video signals (for example, SMPTE 4:4:4 or 4:2:2), standard compressed MPEG-2 4:2:2P@ML signals, or other signals that have undergone only minimal compression, such as the (approximately) 5:1 compression utilized for DVCPRO and DVCAM equipment by Panasonic and Sony. However, the bandwidth required for these high-quality signals still is too great for many broadcast and industrial applications, particularly those that require the level of detail available in HDTV images.
Due to the high-bandwidth demands of high-quality signals, typical distribution systems utilize only the highest quality levels for the head-end equipment and the first part of the signal distribution chain. Furthermore, because of network traffic due to multiple users (as for example, in a cable television distribution system), the last leg of the signal path utilizes a more highly compressed signal, to maximize the usage of the available bandwidth. In most cases, this requires that the original signal be decompressed, and then re-compressed at a much higher compression ratio, so that less bandwidth is required for the final portion of the path.
FIG. 1 is a diagram which illustrates the way in which conventional broadband transmission media are used. Progressive-scan devices are indicated at 102, and include 35 mm film 106, 24 frame-per-second (fps) cameras 108, and the inventive 24P camera system 110 described in further detail herein. Film production and television production are indicated with the vertical box 112, and Internet/broadband applications are shown at 120. Interlace scan devices 114 include 30 fps NTSC 116 and 25 fps PAL 118. Although suitable for certain film and television production applications, interlaced video 114, whether NTSC 116 or PAL 118, is inferior for Internet and broadband applications 120, since the delivered video quality is less than that possible with progressive display, regardless of compression. Even using a progressive format, however, film (35-mm) 106 and high-end 24 fps progressive camera inputs 108 are deficient in terms of quality, due to the need for high levels of compression later in the signal transmission path.
Accordingly, the need remains for an approach to video production and monitoring which allows the levels of quality that users have come to expect at their receiving terminals, while utilizing existing broadband media and other conventional technologies to optimize the signal storage, processing, and transmission path performance.